Civil construction in Ontario

STA 0+120Excavation and trench rules

Ontario’s occupational health and safety rules set when an excavation must be sloped, shored or boxed, and when an engineer must design the protection.

• Walls of an excavation must be supported by a support system (s. 234(1)); not required for an excavation less than 1.2 metres deep (s. 234(2)(a)), one no worker enters, one cut in sound and stable rock, or one sloped as prescribed¹
• Ontario slope alternatives (s. 234(2)(e)-(g)): Type 1/2 soil walls sloped to within 1.2 m of bottom at min 1V:1H; Type 3 soil sloped from bottom at 1V:1H; Type 4 soil sloped from bottom at 1V:3H¹
• Trench deeper than 6 metres or wider than 3.6 metres requires an engineered support system designed for the specific location and project (s. 235(2))¹
• Every prefabricated (trench box/shield), hydraulic or engineered support system shall be designed by an engineer (s. 236(1)); no prefabricated or hydraulic system in Type 4 soil (s. 237(1)(a)) except pipe-break repair systems designed for max 3.6 m¹
• Level area at least 1 metre from the upper edge of each excavation wall kept clear of equipment, spoil and materials (s. 233(1)); barrier at least 1.1 m high where a person could fall into an excavation more than 2.4 m deep (s. 233(4))¹
• Soil classified as Type 1, 2, 3 or 4 (s. 226); mixed soils classified as the highest-numbered type present (s. 227(3))¹
• Before an excavation is begun, the employer excavating shall ensure all gas, electrical and other services in and near the area are located and marked (s. 228(1))¹

STA 0+240Locates before you dig

• Ontario One Call is the province's legislated one-call notification system; online portal²
• A member receiving a standard locate request must mark its infrastructure (or state none is affected) within five business days after notification (s. 6(3)), unless a different time limit is agreed in writing or prescribed (s. 6(5))²
• For an emergency request a member must have a person at the site, or provide the no-conflict statement, within two hours (s. 6(4))²
• An excavator shall not submit a standard request more than 30 days before an excavation or dig is expected to commence (s. 12(1)); excavator must not commence until locates are provided (s. 10(1))²
• Members may not charge a fee for providing locates in response to a locate request (s. 6(7))²
• New regulation 'Continuation to Dig After Expiry of Validity Period' takes effect November 1, 2026; eligible projects may continue digging without a relocate for up to 180 days from the last locate document³

The paint colours are the same across Canada: white for the proposed excavation, pink for survey, then red, yellow, orange, blue, green and purple for the buried services. See call before you dig.

STA 0+360Holdbacks and prompt payment

• Each payer on a contract or subcontract under which a lien may arise shall retain a basic holdback equal to 10 per cent of the price of services or materials as actually supplied, until liens against it have expired or been satisfied (s. 22(1)); separate 10% finishing-work holdback after substantial performance (s. 22(2))⁴
• Mandatory annual payment of accrued basic holdback - following each contract anniversary the owner publishes a notice of annual release (not later than 14 days after the anniversary) and pays the accrued holdback at least 60 but not later than 74 days after the notice, unless liens are preserved (s. 26(2)-(4), added by 2024, c. 20, Sched. 4)⁴
• Owner shall pay a proper invoice no later than 28 days after receiving it (s. 6.4(1)); a notice of non-payment must be given no later than 14 days after receipt (s. 6.4(2))⁴
• Contractor who receives full payment of a proper invoice shall pay each subcontractor no later than seven days after receiving payment (s. 6.5(1))⁴
• A party to a contract or subcontract may refer a dispute respecting any prescribed matter (or any agreed matter) to adjudication (s. 13.5)⁴

STA 0+480Seasonal load restrictions

• During a reduced load period no commercial motor vehicle or trailer shall be operated on a designated highway where the weight on an axle exceeds 5,000 kg (HTA s. 122(1)); 7,500 kg for heating-fuel tankers, livestock-feed trucks and live poultry (s. 122(2)); MTO designates start/end dates (s. 122(5))⁵
• Live seasonal (reduced) load restrictions are published on Ontario 511⁶

Plan haul routes and deliveries around the restriction period. See spring road bans.

STA 0+600The market

Capital spending on engineering construction in Ontario was $39.0 billion in 2024⁷, out of $155.8 billion nationally⁷. The province’s allocation under the Canada Community-Building Fund (now the Community stream of the Build Communities Strong Fund) was $890,735,000 in 2023–24⁸.

STA 0+720Tenders, associations and specifications

• Provincial portal: Ontario Tenders Portal (CanadaBuys page still lists legacy ontariotenders.bravosolution.com; current Jaggaer host ontariotenders.app.jaggaer.com)⁹
• Federal work in the province: open CanadaBuys construction notices
• Ontario Road Builders' Association (ORBA): orba.org¹⁰
• Ontario Sewer and Watermain Construction Association (OSWCA): oswca.org¹¹
• Ontario Provincial Standards (OPSS specifications and OPSD drawings) created in 1977 by MTC/MTO, the Municipal Engineers Association and MOE (now MECP); published free of charge via the MTO Technical Publications website since 2005; published in April and November; use by the province or municipalities is not mandatory¹²
• OPS library (MTO Technical Publications)¹³
• List T1 Construction and Material Specifications and List T2 Standard Road Works Drawings; many Toronto (TS) specs are amendments to OPSS.MUNI (e.g., OPSS.MUNI 1010, 1101, 1151); revisions dated through September 2025¹⁴